WindowServer: If a menu can't fit on screen, at least put it at y=0

We're gonna need to handle overflow better than this, but at least this
way we can see the top of the menu, even if we can't scroll down to see
the rest of it.

For #1043.

Servers/WindowServer/WSMenu.cpp

@@ -409,11 +409,15 @@ void WSMenu::popup(const Point& position, bool is_submenu)
 
     const int margin = 30;
     Point adjusted_pos = position;
-    if (adjusted_pos.x() + window.width() >= WSScreen::the().width() - margin) {
-        adjusted_pos = adjusted_pos.translated(-window.width(), 0);
-    }
-    if (adjusted_pos.y() + window.height() >= WSScreen::the().height() - margin) {
-        adjusted_pos = adjusted_pos.translated(0, -window.height());
+    if (window.height() >= WSScreen::the().height()) {
+        adjusted_pos.set_y(0);
+    } else {
+        if (adjusted_pos.x() + window.width() >= WSScreen::the().width() - margin) {
+            adjusted_pos = adjusted_pos.translated(-window.width(), 0);
+        }
+        if (adjusted_pos.y() + window.height() >= WSScreen::the().height() - margin) {
+            adjusted_pos = adjusted_pos.translated(0, -window.height());
+        }
     }
 
     window.move_to(adjusted_pos);